[v7] usb: gadget: uvc: configfs: Add bFrameIndex attributes

[Felipe Balbi <felipe.balbi@linux.intel.com>]

Laurent Pinchart <laurent.pinchart@ideasonboard.com> writes:

> From: Joel Pepper <joel.pepper@rwth-aachen.de>
>
> - Add bFrameIndex as a UVCG_FRAME_ATTR_RO for each frame size.
> - Automatically assign ascending bFrameIndex to each frame in a format.
>
> Before all "bFrameindex" attributes were set to "1" with no way to
> configure the gadget otherwise. This resulted in the host always
> negotiating for bFrameIndex 1 (i.e. the first framesize of the gadget).
> After the negotiation the host driver will set the user or application
> selected framesize, while the gadget is actually set to the first
> framesize.
>
> Now, when the containing format is linked into the streaming header,
> iterate over all child frame descriptors and assign ascending indices.
> The automatically assigned indices can be read from the new read only
> bFrameIndex configsfs attribute in each frame descriptor item.
>
> Signed-off-by: Joel Pepper <joel.pepper@rwth-aachen.de>
> [Simplified documentation, renamed function, blank space update]
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

please rebase on testing/next, but give me a couple hours to go through
the rest of my inbox first ;)

checking file Documentation/ABI/testing/configfs-usb-gadget-uvc
Hunk #1 succeeded at 177 (offset -4 lines).
Hunk #2 succeeded at 228 (offset -8 lines).
checking file drivers/usb/gadget/function/uvc_configfs.c
Hunk #1 succeeded at 720 (offset -121 lines).
Hunk #2 succeeded at 757 (offset -133 lines).
Hunk #3 succeeded at 996 (offset -137 lines).
Hunk #4 succeeded at 1179 (offset -137 lines).
Hunk #5 FAILED at 1395.
1 out of 5 hunks FAILED